SV101783.JPGOpen Baffle Speakers - Front5760 viewsI had a very large sheet of 18mm particle board which had been sitting around for years. Also a pair of titanium domed tweeters and 2" domed mid-range surplus. What to do with them? With the addition of a pair of cheap but very robust 10" woofers and a 2nd order Xover (600Hz & 3.5kHz) I thought a may knock-up a pair of OBs.

I allowed one day to build these from scratch and with the assistance of some massive angle brackets and a few meters of darcon here is the result. That total height and depth of the speakers is covered in two thick layers of darcon leaving only the woofer rears bare.

The woofers are stiff and require many hours of play to get them to full performance. But the speakers have an excellent sound stage bright mids and highs. Bass is OK but not deep.Aug 30, 2008

Jordan-JX92S-Sealed-Speaker.jpgJordan JX92S in Sealed Speaker Box5984 viewsThe Jordan JX92S Fullrange transducer in a sealed (acoustic suspension) enclosure. The box volume is 5.2L and a camphor burl veneer was used for the finish. I use these with no baffle step correction whatsoever and are mated with an 8" subwoofer from av123.

DSC00006_-_Copy.JPGDual stacked dual driver SoundSplinter subwoofers6846 views5 cu ft subwoofers with the SoundSplinter 15" drivers and 4- AE 15" flat passive radiators in each cabinet. I have them stacked or co-located to act as a single subwoofer. These subs model out to 13 hz at 1000 watts. Each subwoofer has a 1450 watt pro amplifier with the Reckhorn B-1 bass management system to control all frequency duties.Aug 24, 2008

Jordan-JX92S-Bass-Reflex-Speakers.jpgSmall Bass Reflex Speakers with Jordan JX92S Drivers6126 viewsA pair of small vented (bass reflex) bookshelf speakers. A single Jordan JX92S fullrange driver is used per loudspeaker. The Jordan is much better than Fostex drivers at producing bass and it does not need an expensive tube amplifier.Aug 23, 2008

PhonoInside.JPGPhono Preamp Ki.3495 viewsThe cct. brd was assemble and the ABS plastic case drilled ready for assemble. ABS is a very hard plastic to drill. Before assembly the lid, base and sides were lined with heavy tar and foil stick-on shielding. This helps with case dampening also. All gold RCA connections were kept to the rear (see other photos). The chips are the LM833s but the Burr-Brown OPA2134 high performance chip can be directly substituted. The on-board +/- 12V regulated PS is shielded from the rest of the sensitive cct. Additional snubbing was added to the line caps to remove PS noise and chip RF decoupling. Though three different compensation can be selected from the cct. brd by moving two jumpers the lid must be removed to do this. A double pole rotating three position switch could be added to provide this facility externally. The cct. includes a gain control which is accessed from the front and allows easy and silent level adjustment. The sound is natural with no hiss or hum. Easy to build.Aug 20, 2008

PhonoRear.JPGDIY Phono Preamplifier Kit2680 viewsThe finished kit (see other photos) can be assembled in an afternoon. I used insulated gold plated RCAs but on an ABS plastic case like this insulated RCAs are not required. Keeping all connections on the rear makes for a simple front panel with gain control and recessed red led. I used thick silicon stick-on feet to ensure vibration into the unit is kept to a minimum. Stick down computer stand-off hold the cct. brd. to the bottom of the case and also help with vibration control. The case is lined with heavy sticky tar and foil. Base, sides and lid and are lined but not earth. This helps with shielding the low voltage levels and case dampening also. Shielded wiring is used internally and silver solder used throughout.Aug 20, 2008

PhonoFront.JPGPhono Preamp Kit with RIAA Equalization2709 viewsAfter resurrecting the Rega TT and RB300 tone arm with a Grado Sonata wood body cartridge I went on the hunt for a phono preamp. The Pro-Ject PhonoBox SE preamp was a value for money purchase, a neat and good sounding unit. This phono premp kit cost under $AU100 to build (including AC adapter) and challenges the Pro-Ject on a the sonic level. I can find no fault musically with the kit which has no hiss or hum and a natural sound quality. It is available from Jaycar Australia. Better than the Pro-Ject by provide the facility to have three different selectable compensations including RIAA and early DECCA (ffrr) and a host of others to select from. And to go one step better again there is a gain control to balance between CD and phono input levels. The case is ABS plastic and tar and foil lined. Gold RCAs used (see other photos). A +/- 12V regulated PS is include on the one peace cct. brd. The PS is shielded. Distortion is rated at .014% and RIAA accuracy is better than 1db. Signal to noise is -84dB.Aug 20, 2008